<p>This study investigated behavioural and electrophysiological (EEG) markers of decision-making type (individual or group) among professionals, while mentally representing an ideal and real workgroup. Sixty professionals were faced with a critical decision-making scenario, where they were prompted to mentally represent both an ideal and real group and to rate eight items to explore their propensity towards individual or group decisions. EEG activity was collected during the task (measuring frequency band power: delta, theta, alpha, beta, and gamma). Behavioural findings revealed that professionals tended to lean towards group decision-making, showing consistency in this decision-making type regardless of whether they mentally represented an ideal or real group. EEG markers showed evidence in the delta, alpha, and gamma bands. The delta band suggested that the real compared to the ideal mental representation is linked to heightened motivational processes and positive affect associated with rewarding experiences. The alpha band indicated that when envisioning an ideal scenario, group decision-making required less cognitive effort and stress, likely because it was easier to envision a unified group decision in an ideal setting. Finally, the gamma band suggested that, in a real representation, adopting a group decision-making approach demanded greater neurocognitive resources and mental effort, perhaps due to the need to integrate diverse perspectives. Overall, this study sheds light on individual and group decision-making and mental self-representation among professionals. EEG markers provide deeper insights into the neural distinctions between professionals’ ideal and real representations of group decision-making. Findings suggest that bridging the gap between idealized and real group dynamics within organizations could be beneficial for practitioners, as it can improve decision-making and group cohesion.</p>